THE RHIPICEPHALARIA 597 



carefully studied the life history of Ixodes pilosits, the so-called ' paralysis 

 tick ' of South Africa. This tick is essentially a parasite of warm- 

 blooded animals, and appears to thrive best on the ox, 



sheep and goat, though it has been found on many "'' hi * tory , f 4 ' ck8 



of the genus Ixodes. 



other animals and even on man. It prefers to attach 



itself to the head, and especially to the ears, but may be found on any part 

 of the body. The larval pilosus takes about two or three days to become 

 replete with blood ; this time may, however, be greatly lengthened. 

 It then drops off and seeks a hiding place, where it slowly digests its 

 food and later becomes transformed into the nymph. It again seeks a 

 host, to which it remains attached for three days ; it then drops off and 

 slowly becomes transformed into the adult. If both sexes become attached 

 to the third host at the same time copulation take place, and the female 

 becomes replete with blood in from five to six days. This type of life 

 history is common to the majority of the Ixodidae and is a relatively 

 simple one ; it should, however, be clearly understood that it does not 

 necessarily follow that the nymph will attach itself to the same species 

 of animal as that on which the larvae fed, and the adult to the same 

 species on which the nymph fed ; each stage may feed on a different 

 species of mammal or reptile. 



TRIBE RHIPICEPHALARIA 



Anal groove (sometimes absent ) contouring the anus posteriorly, arms 

 extending anteriorly and joining the genital grooves at the level of the 

 spiracles. Palps hollowed out internally ; eyes present. Usually eleven 

 festoons along the posterior border. Scutum sometimes marked with 

 clear spots. Ventral surface of male with four plates or shields; a 

 quadrangular adanal plate at each side of the anus and an accessory 

 triangular one, which is smaller and situated external to the adanal. 

 (Neumann) 



Neumann gives the following key to the genera : 



NEUMANN'S KEY TO THE GENERA OF RHIPICEPHALARIA 



Capitulum short, basis capituli with lateral projections ; 



spiracles sub-triangular. Anal grove present . . Rhipicephalus. 

 Capitulum short, basis capituli with lateral projections ; 



spiracles circular or oval. Anal groove absent . Margaropus. 



Capitulum long, basis capituli without projections, lateral 



borders straight and parallel ; spiracles sub-triangular. 



Anal groove present . .... . . ' Hyalomma. 



